ASB EC135-21A-013

Revision 0, 2011-06-06 PAGE 1 of 11

Effective for version(s): T2+, P2+, 635 T2+, 635 P2+

EMERGENCY

ALERT SERVICE BULLETIN

SUBJECT: AIR CONDITIONING -- Mechanical air conditioning

Inspection of the compressor bearing block

Revision number Issue date

Revision 0 2011-06-06

Summary:

During the preflight check metallic parts have been found within the area of the air inlets of both

engines. The following inspection showed that these parts were parts of the bearing cage of one of

the ball bearings of the air conditioning compressor bearing block. Loose parts of the bearing cage

have damaged the compressor stage of one of the two engines to such an extent that a basic overhaul

was necessary. Therefore, this Alert Service Bulletin specifies an inspection of the affected ball

bearing.

Compliance:

Compliance with this Alert Service Bulletin is prescribed. See Section 1.E.

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1. PLANNING INFORMATION

1.A. EFFECTIVITY

1.A.1. Helicopters/installed equipment

(a) EC135/EC635, all models with mechanical air conditioning S/N 870, 872, 873, 879, 883,

884, 888, 893, 900, 905, 911, 914, 916, 917, 923, and 926.

(b) Compressor bearing block P/N L210M1872105*.

* The part number is on the place identified on Figure 1. Compressor bearing blocks L210M1872106 and L210M1872107

are not affected.

1.A.2. Non--installed equipment

Not applicable

1.B. ASSOCIATED REQUIREMENTS

Not applicable.

1.C. REASON

During the preflight check metallic parts have been found within the area of the air inlets of both

engines. The following inspection showed that these parts were parts of the bearing cage of one

of the ball bearings of the air conditioning compressor bearing block. Loose parts of the bearing

cage have damaged the compressor stage of one of the two engines to such an extent that a basic

overhaul was necessary. Therefore, this Alert Service Bulletin specifies an inspection of the

affected ball bearing.

1.D. DESCRIPTION

Remove LH and RH transmission fairings. Open bearing block cover. Inspect bearing for

condition. If necessary, deactivate air conditioning.

1.E. COMPLIANCE

1.E.1. Compliance at the works

Not applicable.

1.E.2. Compliance in service

Helicopters/installed equipment:

(a) The upper bearing must be inspected i.a.w. Section 3.B.2 within 25 fh after receipt of this

Alert Service Bulletin, but by June 30, 2011 at the latest.

(b) If water or corrosion is detected during the inspection i.a.w. Section 3.B.2 deactivate the

air conditioning i.a.w. Section 3.B.3.

(c) If no water or corrosion is detected during the inspection i.a.w. Section 3.B.2 this inspection

must be repeated every 100 fh (with a tolerance range of +/--10 fh) but after 3 months at

the latest.

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(d) If only condensation moisture (without formation of troplets) is detected during the

inspection i.a.w. Section 3.B.2 the inspection must be repeated every 25 fh (with a

tolerance range of +/-- 2.5 fh) but after 4 weeks at the latest.

Non--installed equipment:

Not applicable.

1.F. APPROVAL

Approval of this document:

The technical content of this document is approved under the authority of

DOA No. EASA.21J.034.

1.G. MANPOWER

Qualification Mechanic Electrician Pilot Others

Time for Section

3.B.2 approx. 4 h 0 h 0 h 0 h

Time for Section

3.B.3

approx. 6 h 0 h 0 h 0 h

1.H. WEIGHT AND BALANCE

Not applicable.

1.I. EFFECT ON ELECTRICAL LOADS

Not applicable.

1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD

Not applicable.

1.K. REFERENCES

Not applicable.

1.L. OTHER DOCUMENTS AFFECTED

AMM EC135 and AMM EC135/635.

1.M.INTERCHANGEABILITY OR MIXABILITY OF PARTS

Interchangeability:

Not applicable.

Mixability:

Not applicable.

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2. MATERIAL INFORMATION

2.A. MATERIAL: PRICE -- AVAILABILITY -- PROCUREMENT

Not applicable.

2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

Not applicable.

2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/COMPONENT

Kits or components to be ordered for one helicopter or one assembly:

Material kit SB-135-21A-013-2C.

No. Keyword Qty New P/N Old P/N Remark

1 O--ring 1 0634313273 0634313273 --

2 Hexagon nut 6 LN9338--06 LN9338--06 --

Consumable material to be ordered separately:

Consumable materials must be separately ordered at the INTERTURBINE AVIATION

LOGISTICS company. The given CM -numbers are i.a.w. the AMM List of Consumable Materials.

Website: http://www.interturbine.com

Tel.: +49.41.91.809.300

AOG: +49.41.91.809.444

No. Keyword Qty Material

part number

CM Remark

1

Acetone a.n.* FED O--A--51

TL 6810--003

203

--

2 Lockwire, Ø 0.63 mm a.n.* LN9424--1.4546.9--0,63 775 --

3

Corrosion preventive paste

a.n.*

ECD CODE 62888 / 54456

MIL--PRF--8116

WL 5.7070.0

CMS N4911651774

LN9368--5903

518

--

4

Sealing compound

a.n.*

WL 5.5905.2

ECD CODE 810421

CMS N4915080001

6050

--

5

Sealing compound a.n.* ECD CODE 658971

WL 5.5904.2

6056

--

*a.n. = as needed

2.D. MATERIAL TO BE RETURNED

Not applicable.

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Revision 0, 2011-06-06 PAGE 5 of 11

3. ACCOMPLISHMENT INSTRUCTIONS

3.A. GENERAL INFORMATION

Not applicable.

3.B. OPERATIONAL PROCEDURE

3.B.1. Preliminary steps:

(a) Remove the LH and RH transmission fairing i.a.w. AMM, 71--11--00, 4--4.

3.B.2. Inspect bearing:

NOTE

On helicopters with sand filter the rotor mast seal must be removed previously.

(a) Remove lockwire (1, Figure 2).

(b) Remove screws (2) and washers (3).

(c) Remove cover (4).

(d) Accomplish a visual inspection of the bearing and the bearing housing for humidity and

corrosion.

(e) If signs of water or corrosion are detected, proceed i.a.w. Section 3.B.3.

NOTE

If necessary, use a flashlight.

(f) If no signs of water or corrosion are detected, proceed as follows:

1 Clean sealing surface on the cover (4) and on the compressor bearing block using

a lint--free cloth and acetone (CM 203).

2 Leave cleaned areas to air for approx. 10 minutes.

3 Apply sealing compound (CM 6056) and fit cover (4).

4 Apply corrosion preventive paste (CM 518) onto screws (2) and secure cover (4) using

screws (2) and washers (3). Tightening torque of the screws: 4--5 Nm.

5 Safety screws (2) with lockwire (CM 775) i.a.w. Figure 2.

3.B.3. Deactivate air conditioning:

NOTE

On helicopters with sand filter the rotor mast seal must be removed previously.

(a) Remove the screw (2, Figure 3) installed on the LH aft side, as seen into forward flight

direction, together with washers (3), nut (6) and the bracket (4) of the brake line (5).

(b) Remove the screw (12) installed on the RH aft side, as seen into forward flight direction,

together with washers (3, 14), nut (6) and grounding strip (13).

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(c) Remove the nuts (6) together with washers (3) from the LH and RH aft threaded bolt.

(d) Remove the nut (6) installed on the RH forward side, as seen into forward flight direction,

together with the washer (3) from the threaded bolt.

(e) Remove the screw (6) installed on the LH forward side, as seen into forward flight direction,

together with washer (3) and the bracket (10) of the brake line (5) from the LH forward

threaded bolt.

(f) Discard all removed 6 nuts (6).

(g) Set brake line (5) aside.

CAUTION

IF THE COMPRESSOR BEARING BLOCK (1) TILTS, THE CONNECTING SHAFT (9) MIGHT

GET DAMAGED. CAREFULLY LOOSEN THE COMPRESSOR BEARING BLOCK (1)!

(h) The bearing block is installed with sealing compound. If necessary, detach the compressor

bearing block (1) from the flange (7) on the main transmission using plastic wedges and

with slight hammer strokes.

(i) Lift the compressor bearing block (1) and keep it at a certain distance towards the main

transmission using tensioning straps.

(j) Remove connecting shaft (9).

(k) Remove the O--ring (8) on the lower side of the compressor bearing block (1) from the

centering seat and discard.

(l) Apply lubricating oil CM 103 or lubricating oil CM 1001 onto new O--ring (8) and install it

to the lower side of the compressor bearing block (1) in the groove of the O--ring on the

centering seat.

(m) Clean flange (7) on the main transmission and on the compressor bearing block (1) using

a lint--free cloth and acetone (CM 203).

(n) Leave cleaned area to air for approx. 10 minutes.

(o) Evenly apply corrosion preventive paste (CM 518) onto the flange (7) of the main

transmission and onto the four threaded bolts.

(p) Position the compressor bearing block (1) onto the flange (7) of the main transmission.

While doing so ensure that:

1 The four forward boreholes in the flange of the compressor bearing block (1) align with

the four threaded bolts on the flange (7) of the main transmission.

2 The two aft boreholes in the flange of the compressor bearing block (1) align with the

boreholes on the flange (7) of the main transmission.

(q) The previously discarded nuts (6) are replaced by 6 new nuts (6).

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(r) Using nut (6) and washer (3), secure the bracket (10) on the threaded bolt installed on the

LH forward side, as seen into forward flight direction.

(s) Torque--tighten nut (6) to 9 Nm -- 10 Nm.

(t) Install nut (6) and washer (3) onto the threaded bolt installed on the RH forward side, as

seen into forward flight direction.

(u) Torque--tighten nut (6) to 9 Nm -- 10 Nm.

(v) Install nuts (6) and washers (3) onto the two remaining threaded bolts.

(w) Torque--tighten nuts (6) to 9 Nm -- 10 Nm.

(x) Using screw (2), washers (3) and nut (6), secure the bracket (4) of the brake line (5) to the

borehole on the LH aft side, as seen into forward flight direction. While doing so, install the

screw (2) with corrosion preventive paste (CM 518).

(y) Torque--tighten screw (2) and nut (6) to 9 Nm -- 10 Nm.

(z) Using grounding strip (13), screw (12), washers (3, 14) and nut (6), prepare the grounding

connection i.a.w. AMM, 20--00--00, 2--21. Install the screw (12) with corrosion preventive

paste (CM 518).

(aa) Torque--tighten screw (12) and nut (6) to 9 Nm -- 10 Nm.

(ab) Remove protruding corrosion preventive paste (CM 518) from flange (7) of the main

transmission.

(ac) Remove protruded corrosion preventive paste (CM 518) also from the inner contour of the

compressor bearing block (1).

(ad) Thoroughly clean the area around the flange (7) using a lint--free cloth and acetone (CM

203).

(ae) Leave cleaned area to air for approx. 10 minutes.

(af) Seal inner area of the compressor bearing block (1):

1 Apply CM 5003 corrosion preventive paste onto the surface of the main transmission

and onto the inner contour of the compressor bearing block (1). Leave to dry i.a.w. the

manufacturer’s instructions.

2 Apply CM 526 corrosion preventive paste onto the surface of the main transmission

and onto the inner contour of the compressor bearing block (1). Leave to dry i.a.w. the

manufacturer’s instructions.

(ag) Protect grounding connection i.a.w. AMM, 20--00--00, 2--21.

(ah) Apply a sealing compound bead (CM 6050) around the outer contour of the flange (7).

(ai) Let sealing compound dry i.a.w. the manufacturer’s instructions.

(aj) Immediately after accomplishment of the measures of this Alert Service Bulletin the pilots

must be informed of its contents and their attention must be drawn to the fact that the air

conditioning is deactivated.

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3.B.4. Final steps

NOTE

On helicopters with sand filters the rotor mast seal must be re--installed.

(a) Install the LH and RH transmission fairing i.a.w. AMM, 71--11--00, 4--4.

3.C. IDENTIFICATION

Accomplishment of this document:

Confirm accomplishment of this Alert Service Bulletin by an entry in the historical record of the

helicopter.

4. APPENDIX

Not applicable.

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Revision 0, 2011-06-06 PAGE 9 of 11

Part Number on the Bearing Block

Figure 1

View A

1 Bearing block

1

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Inspection of Upper Bearing

Figure 2

1 Lockwire (CM 775)

2 Screw

3 Washer

4 Cover

Visual inspection of the bearing housing and the

ball bearing for humidity and corrosion.

Sealing surface of cover

1

2, 3

4

x4

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Removal of Connecting Shaft

Figure 3

View A

ViewB

B

View C

1 Compressor bearing block

2 Screw

3 Washer

4 Bracket

5 Brake line

6 Nut LN9338--06

7 Flange

8 O--ring 0634313273

9 Connecting shaft

10 Bracket

11 Not applicable

12 Screw

13 Grounding strip

14 Washer

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